Gasification of powdered caking type coal



Dec; 8,-1953 N. L. DlcKlNsoN cAsIFIcATIoN oF PowDEREn cAxING TYPE coALFiled June 2. 1947 l .'5 Sheets-Sheet 1 Dec. 8, 1953 N. L, DlcKlNsoNGASIFICATION OF POWDERED CAKZINGv TYPE COAL s sheets-sheet 2v Filed June2. 1947 INVENToR.

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Dec. s, 1953 N DICKINSON 2,662,007

GASIF'ICATION OF POWDERED CAKING TYPE COAL 7 Trams/@ Patented Dec. 8,`1953 GAsIFlcA'rIoN oF PowDERED canino TYPE ooAL Norman L. Dickinson,Basking Ridge, N. J., as-

signor to TheM. W. Kellogg Company, Jersey City, N. J., acorporation ofDelaware e Application June 2, 1947, serial No. 751,728

uolaims'.

rThis invention relates to the treatment of carbon-containing material.In one vaspect this invention relates to the high temperature treatmentof solid carbon-containing materials, such as coal and coke. Morespecifically, in one aspect this invention relates tothe production of agas rich in hydrogen from coal or other solid carbon-containingmaterials.

- It has been known 4for some time that coal maybe treated with oxygenand steam at relatively high temperatures to convert the coal tohydrogen and carbon monoxide,v which products are useful for thesynthesis of organicV compounds. In general, coal, coke, 4or othercarbon-bearing solid materials are-contacted with oxygen and steam in anamount of about cubic feet of oxygen per pound of steam per pound ofcoal at a temperature aboveabout 1000 F. under conditions such that thecarbon, steam, and'oxygen are converted to hydrogen and carbon monoxide.rVarious methods have been practiced to eiiect the gasiiication of coalto produce a gaseous eiiiu-` ent rich in hydrogenv and carbon monoxide.Among these methods is that known as the Lurgi process, which comprisescountercurrently contacting a `moving bed Aof crushed or ylump coal withan upward flowing mixture of oxygen and steam. A temperature vbetweenabout 600 F. and about l600 F. or--higher is maintained between the topand bottom, respectively, of ,the moving bed of coal and apressure oflabout 200 or 300 pounds per square inch gage is maintained during thegasiiication process. This processis v characteristic of producing agaseous eflluent containing hydrogen, carbon monoxide, and considerablequantities of carbon dioxide and methane.

Also, among these known methods for the gasif iication of coal is theWinkler process which com-.- .prises passing oxygen and steam through asocalled fiuid bed of finely divided coal at ay temperature of about1600 F. to 1800 F. and at about atmospheric pressure or slightly above.The Winkler process is characterized by an operation using apseudo-liquid dense phase of coal achieved by passing a gaseous mixtureupward through pulverized coal having a size of. about 0.5 inch processhas several apparent advantages over other processes, such as the movingbed type operation. One of these advantages is the fact that the-Winklerprocess or uid-bed process produces hydrogen and carbon monoxide withonly minor amounts of methane, which fact is desirable when the productis to be used for the synthesis of hydrocarbons. Even in view of therelatively good results obtained bythe iiuid-bed type operation, certaininherent disadvantages have been found. In such iiuid-bed roperations inwhich the ly divided suspended'coal and maintain the nely divided coalcontinuously in a iiuidized condition. The sticking or caking of thecoal particles limits the use vof the` Winkler processto special gradesof coals which do not have this tendency to stick at high temperatures.It is desirabletherefore, to provide a processand apparatus whichovercome'these difliculties. f t Anobject of this invention is toprovide a proc-` ess and apparatus for the gasiiication ofcarboncontaining'solid materials.V n NAnother object of this inventionis to provide a process forthe production of hydrogen fromcarbon-containing solid materials.

Further, another object of this-inventionis to provide a process for theproduction of coke from coal. v v f 'It is a further object of thisinvention `to pro.- duce hydrogen-and carbon monoxide from coal.- `Yetanother object of this invention is to produce a gas `of relatively highheating value. Still another object of this invention is to pro- 'vide amethod for the' recovery of volatile comin diameter such that thepulverized coal is suspended in the gaseous mixture under the conditionsof operation. In the Winkler operation a relatively low upward gasvelocity characteristic 50 of .that necessary to produce apseudo-liquidflmd- It is an objectY to provide'a coal gasication' inhydrogen and carbon monoxide by suspendingv or ent-,raining finelydivided solidmaterialcontaining carbon in a stream of oxygen and steam.at relatively high temperatures and high prSr.

sures. According to this invention, finely divided coal is introducedinto a rapidly flowing gaseous' stream of oxygen and steam underconditions such that the heaviest particles are continuously? 1 moved byentrainment in the direction f fio wA Y 4 pass. The reaction zone shouldbe of such length with regard to the gas velocity that sufficientresidence time is provided for substantially complete gasification.However, the reaction zone may be of such length to provide insufficientresidence timefor complete gasification of the coal in one pass, and insuch case unconverted coal is recycled to the reaction zone to completethe gasification thereof.

Various solid carbon-bearing materials may be employed and Can'beconverted to hydrogen and 'carbon monoxide according to the techings ofthisliiiyention.l Such carbon bearing materials compriseivaroustypes ofcoal, such as anthraof the gaseous stream. The linear velocity'of theditions o f velocity,` the conventional pseudo-liquid or fiuidized densephase of nely dividedparticles is not formed but instead a dilute phaseof finely divided and highly dispersed particles is produced whichpermits much higher temperatures of reac-` tion than heretofore possiblewith conventional nuid-bed type operations using comparable qualitycoals.v Pressures from about 100 to about 1000 pounds per square inchgage and temperatures from above about 1400 F. to about 2600o F. areemployed. At the high gas velocities and degree of dispersionof thecoalY and this inventiomsubstantially complete conversion of the carbonto hydrogen' and carbon monoxide can be effected at A high temperatureswithout agglomeration.

bite, -bituminous,` sub-bituminous, lignite, and

various types of coke, such as coal coke and petroleum/coke; Poor gradesof coal may be used in this process because little opportunity isaforded for agglomeration of the coal particles at suchhigh velocitiesandA at such low concentrations encountered in the process of thisinvention. Furthermore, since the tendency of the carboncontainingmaterials to agglomerate or fuse in the reaction zonev is practicallyeliminated, relatively higherV temperatures can be used, if desired,than in other conventional coal gasification processes. For example, atpressures above about 25() pounds per square inch gage and attemperatures above about 1800 F., a gaseous effluent containing hydrogenand carbonmonoxide substantially' free from methane is obtained. Such agaseous effluent is highly desirable for subsequent use fortheconversion thereof to organic compounds by various known synthesisprocesses'.

For the gasification ofk coal or other-solid carbon-containing materialsaccording to the present invention, the coal must be in a finely dividedpowdered form. yPreferably, the powdered solid material initiallycontains no more than a minor Operationsaccordingto this invention alsoen able a large capacity per unit volume of sizeof equipment. Methanecan be'produced together with hydrogen and carbon monoxide according to.one embodiment'of the present process by, us;- ing temperatures lowerthan. 1800" F. andas low 21.5.. about 1000 F. IIhus, when it isdesirable to producemethane along with. hydrogen and. carbon monoxide,such as for fuel purposes, this rnay be done conveniently byregulatingthe temperature along Vwith such other conditions as resi@dence time of the coal andthe ratio of steam and oxygen.

Generally, the ratio of oxygen to coal, and steam lto coal may be variedfrom about 4 to about 15 cubic f eet of oxygen per pound of coal andfrom about 0.2 to about 5 pounds of steam perV pound of coal,respectively. The proportion of oxygen, steam, andcoal is regulatedwithinthe above ranges to control the temperatureofconversion and alsotovr control theconversion'. of

coal per pass fora given residencetime of coal. As the interactionbetween steam v'andjcarbon is endothermic and thatbetween oxygen and carbon is exothermic, sufficient oxygen must be in troduced intotheconversion Voneto maintain the desired temperature of reaction.

Complete conversionor gasiication ofthe coa to gaseous products. whenoperating according to this process is achieved -by a residencevtimeofthe carbn-containing. material. in the.. reaction vlor proportionby weight of material vwhose average particle'diameter is greater thanabout 250 microns. Anexample of a desirable powdered coal is one inwhich about '7 5 to 95 per cent by weight passes through a 200 meshscreen. The pulverizationof the coal may be effectedl by variousconventional` means,v such as by grinding in a ball milhas, byconventional equipment known as the Micronizen'or by explosionpulverizetion; without'` departing from the scope of this invention.

Generallyl lthe reaction zone itselfV Will comprise a single conduitortube of an inside diameter between about 1 and about 6 feet.Preferably, the reaction tube is of sufiicient length withrespeci;` tothe velocity ofthe gases therein that substantially complete gesincation of the carbon- 'containing material is effected in asinglepass andmay containY baffles and/or orifice plates to obtainthedesiredturbulence, especially in the larger diameter reactionchambers.

.This process is distinguishable over those processes which employaffluid-bed typeV operation. In" the fluid-bed type operation, thefinely divided solid materialforms a so-called pseudoliquid., densephase ofsuspended material inthe reaction zone and; consequently thecarbonaceous ma te`rial' remains inthe reaction zone itself in thisdensef iuid beduntilgasiiied or converted. The concentration ofsolid materialin the dense fiuidbed isY rluch greater than the concentration o1?sclidmaterialin the reaction zoneof this` inf vention. Inthedense phaseYprocess the conf eentr'ation isusually greaterthan about 1.0,or 20pounds `of solidA materiali per. cubic foot.. Qf ses .andmay be as highas lOo pounds per. cubieioot of gas atstandard conditions. Usually, inthe.:

conventional pseudo-liquid dense phase process, the reaction zone is ofsuch a volume and crosssectional area and the gas velocity issufficiently low that the nely divided material is suspended in afluidbed with thek presence of a so-called interface 1 of rapidly decreasingconcentration between the fluid-bed and an upper dilute phase. The upperdilute phase contains a small amount of ashand unconverted solids ascarry-over from the dense phase. Usually only a minor proportion of theconversion, if any at all, is effected in the dilute phase; the dilutephase being primarily Va separation zone for preventing the carry-overof solid material from the dense phase. In the Winkler process, themajor proportion of the conversion is effected in the dense phase.

Although the process of ythis invention has been described withreference to an upward owing gaseous stream of steam and oxygen andentrained carbon-containing material, it should be understood that thecarbon-containing material and gaseous reactants may flow togetherdownwardly, horizontally, angularly, or with a circular movement througha reaction zone without departing from the scope of this invention. Inhorizontal, circular, or angular flow the velocity should be sumcientlyhigh to cause turbulent flow thereby preventing settling ofthe i finelydivided coal.

, In yvertical rlcw, the concentration is a function of velocity atrelatively low velocities but as velocity is increased a point isreached where slippage of the solid particles in the gaseous stream isnegligible. At velocities above this point, concentration is a functionof the loading rate (amount of solids forced into the gaseous stream).Preferably, ythe velocity of the gas is such that slippage of the flnelydivided particles of coal is negligible.

The use of finely divided coal of 250 microns or less results in a veryhigh rate of reaction because of the large surface area of the coalparticles. The rate of reaction is also increased by high partialpressures of steam and oxygen, by the extremely short time required forthe coal particles to reach the reaction temperature as the result ofradiant heat transfer unobstructed by high concentration of solidparticles,-and also to some extent by dissociation and ionizationphenomena characteristic of flames. The high rate of reaction in turnenables a large capacity perk unit volume of size of equipment.

rrThe gasification of coal isveffected according to the-followingtypical equations: 'y

" CY-l-H2O- CO+H2 2C|O2 2CO ',"As high as 99.5 per cent overallconversion and as' high as 85 per cent, carbon monoxidel yield based'oncarbon feed is achieved when operating, a' process within the preferredconditions of this invention. The efiluent from theconversion zonecontains on a dry basis about Y30, to about 50 Volume per cent carbonmonoxide,

yabout 35'to'about 55 volume per cent hydrogen,

about to about 20 volume per cent `carbon,

dioxide, and about 0.1 to about 25 volume per cent methane.

This invention will be discussed further by reference to theaccompanying drawings which comprise viewsin elevation, partly incross-section, of' suitable arrangements of apparatusfor carrying out lthe process of the present ini/'efrtion.` Figure 1 of the drawing is anelevational View, partly in cross-section, diagrammatically illustratingan arrangement of apparatus for the' monoxide and hydrogen,; anddiagrammaticallyVv illustrates an elevational view of apparatus,A

partly in cross-section, for suchan embodiment` Figure 4 is a4diagrammatic illustration in ele-v vation of a modification of chamber|28 of Figure 3.. Figure 5 is still another embodiment ofv the presentinvention'-diagrammatically illustrating an elevational View of asuitable arrangement of apparatus for the production of hydrogen andcarbon monoxide from coal.

In Figure l of the drawings crushed coal is introduced through conduitIl into storage vessel l2. The coal, preferably, is of a size such thatit will pass `an -8 to 16 mesh screen. The crushed coal flows fromstorage vessel I2 through a branched conduit I3 into a series ofparallel lockhoppers i4, l, l1, and 18, as shown.' By means of theselock hoppers the coal is raised to a desired pressure for operation ofthe process. In loclf` hoppers lUl and Il the coal therein is pressuredwith a gas introduced through conduits 22 and v23.l In these first lockhoppers the i coal is pressured, for example, to a pressure of about 260to. about 300 pounds per square inch gage. The coalisfthen passed atrthis pressure into the next hoppers, i6 and .18, in which the pressureofthe coal israised by means of aga-s to about 500 to about 600 poundsper square inch gage, or higher. The pressuring gas is introduced intolock hopperswl and i8 through either conduit 'i9 or` conduit 2l. areWorked'alternately in series; that is, one series is introducing thepressured coal into conduit 32under conditions of controlled flow whilethe otherrseries is being pressured. vAfter the coal' has beenintroducedrinto conduit 32 from either of hoppers I6 or i8, for example,hopper I8, the gasesunder the pressure existingin hopper 'i8arelexpanded into hopper Il in which coal has been introducedf, The coalis then passed fromhopper Yllto hopperl at the pressureA existing ,invhopper l'l.-Pressuring gas is introduced into hopper I3 through conduit`2i 0r Aconduit, tte raisegjhe pressure -to'the Yde-y continuouslyinjected ,frornkhoppers I6 and '18.

The resulting mixture is conveyedthroug'h conduit 32`ftoa conventionalexpansion nozzler 34.'

*"In nozzle 34 the steam containing the entrained coal is-I expandedinto conduit 36 to a pressure vlowerthan that pressure existing 'inconduit 32, lusually about to :about 300 pounds per square inch lowerVthan in.conduit.32.": By virtue ofthe sudden .expansion ofthe mixtureof gases and coal in nozzle 34; ther-gases or liquidin the poresof thecoal are also rapidly, expanded causing VPul- The hoppers,

aceaoovif verzat'i'ori f the coal; Some pulverzation may be effected bythe impact between particles in the turbulent wake of `nozzle L34. Thiskexplosion pulverization process reduces the particle size of the coalto a size less than about 250 microns and often less than about 100microns. For low pressures of conversion. su'icient size reduction ofthe coal can be achieved with pressure drops as small as '15 or 50pounds per square inch. The pressure drop across nozzle 34 required toobtain the desired size of coal particles depends on such factors as thedesired sizeof the particles, the design of the nozzle, the nature ofthe solids and expansion medium, ratio of solids to expansion medium,etc. These factors are correlated to give the ldesired particle size.

Natural gas, recycle gas from a synthesis process for producinghydrocarbons and organic compounds from hydrogen and carbon monoxide, orrecycle gas from the coal gasification process itself may be introducedinto Athe system through line 32 and may serve as the carrier gas forthe coal in line 32. Natural gas or recycle gas may be introduced inaddition to or alternatively to the steam from conduit 3l and may beintroduced and admixed in conduit 32 or may be passed through conduitl33 and admixed with the steam and pulverized coal in conduit 36. IThemixture of steam, pulverized coal, and any other gases, such as anatural gas or recycle gas, are passed through conduit 36 to a burner 31and a vertically positioned combustion chamber 38. Burner 31 comprisesai cylindrical chamber in which the gaseous mixture of coal and steam isintroduced at one end lthereof and steam and v oxygen are introducedtogether or separately through a series of perforations or ports throughthe cylindrical shell of the burner, such as through conduits 52 and 53.The coal-containing mixture, the steam, and the oxygen may be injectedtangentially through burner 31 into chamber 38, if desired, in order toimpart a whirling motion to the mixture leaving the burner.

In order to gasify the coal, oxygen `is introduced into 4combustionchamber 38, such as through burner 31. Oxygen may be produced inanyconventional manner in oxygen plant 40, such as by refrigeration andcondensation of air to separate the oxygen therefrom. Substantially pureoxygen, usually between about 90 and about 98 per cent purity, is passedfrom oxygen plant 40 by means of compressor 4l through conduit 42 to aconventional preheater '43. In preheater 43, the oxygen stream is heatedtoa temperature between about 500"` F. and l000 F. Oxygen is passed frompreheater 43 through conduits 44, 52, and 53 to burner 31.

When insufficient steam is supplied from "high pressure steam boiler 29for eifecting the reaction or gasication of the coal in chamber 38, lorfor other reason, additional steam may be introduced into thevsystemthrough conduit 46. Such additional steam is generally at a lowerpressure than steam from boiler 23 and ispassed through a conventionalsuper-.heater 4.1 -in .which the steam is .heated to a Vtemperaturebetween about 750 F. andl'100" Super-heated steam is passed fromsuper-heater 41 through conduits 48 vand 49 to conduit 36 for admixturewith the steam and coal mixturetherein. Alternativelyv or additionally,.thesteam `fromzconduit 48 'may .be introduced andadmixed V.with 'theoxygen in vconduit '5 l .as shown, and then passed 'through `conduits 52:and 53 yizo-burner 31. iPr-ehea-tinglof the reactants reduces thequantity .of oxygen required.

to obtain the desired conversion temperatln'e.

The amount of voxygen supplied `through Lconduits 52 and 53 is betweenlabout 5 and about 15 cubic feet of oxygen .per pound of coal or carbon?bearing material, preferably the amount of oxygen is between about 6 andabout 11 cubic feet per pound of coal. The total amount of steam presentin the system after introduction through conduit 32 and conduit 49 or inadmixture with the oxygen through conduits 52 and 53 is initiallybetween about 0.2 and about 5 pounds of. steam per pound of coal orcarbon-bearing material, and preferably between about 0.4 .and about 2pounds of steam per pound of coal.

Under the conditions in burner 31 the coal is ignited and passes as a`iialne together with the. oxygen and steam from burner 31 into combustion chamber 38. Combustion chamber 38 comprises preferably an elongatedcylindrical conduit or chamber internally insulated with a suitablerefractory material substantially resistant to the high temperatures ofcombustion therein. Com` of combustion chamber 38 is above 1800 F. in'

the preferred embodiment of this invention for the production of agaseous effluent rich .in hydrogen and carbon monoxide and substantiallyfree from methane. The minimum temperature in the range above 1800 F.required to obtain a product free from methane will depend upon. Underthese conditions. of operation and at the high pressures involved" theoperating pressure.

the nely divided coal particles are carried along with the upwardflowing gaseous mixture without the formation of the conventionalpseudoliquid dense phase characteristic of lower velocities. Atvelocities between about 15 and about 50 feet per second the particlesVof c oal are carried along by the gaseous stream substantiallyat thesame velocity -as the Vlinear velocity of the gas. However, someslippage of the solid particles may be evidenced in the vertical cham-.ber 38, but this slippage is usually not much more than about 50V percent in the extreme cases. Under these conditions of operation theconcentration of coal in the gaseous react-ion mixture is Very low,usually between about 0.0-1-

and about 0.5 pounds of Vcoal lper cubic foot of gas at standardconditions of temperature -andpressure. The residence time of the coalin the combustion chamber lis substantially the same as the residencetime of the gas flowing therethrough, or at least the residence time ofthe coal is much shorter than the residence time of the solids in theconventional ,pseudo-liquid phase process. In the preferred embodimentof this invention, combustion chamber 38 is of such length that ,thesolid .particles will remain in the chamber a sufficient length of 'timeto achieve complete gasification thereof; such times usually being lessthan about v5 seconds and Aoftenas low as 1 `or f2 seconds. l

As ypreviously discussed, if it vis .desired to produce a substantial`quantity of methane in-.the ultimate gaseous effluentfromcombustioncham? ber 38, lower temperatures are necessary; 'usuall`the ytemperature isbelow about 1800311. and preferably about 1500 F.depending'upon the; operating'` pressure. The `temperature `of reactionis lowered ,by altering the .ratios `of zoxygen `and,`

.or storage tank 12.

steam to coal as previously discussed. A gaseous effluent containinghydrogen, carbon monoxide, small quantities of ash, carbon dioxide, andsteam, and in some cases methane, is removed from combustion chamber 38and passed through conduit 3-9 to a waste heat boiler 5ft which maycomprise a single or a plurality of boilers. In Waste heat boiler 54 aconsiderable portion of the heat is removed from the gaseous effluentand utilized in producing steam which may be used in the process. Thereaction eluent is passed through tubes 55 of boiler 54 under conditionssuch that the eilluent is cooled to atemperature of about 1000 F. orlower.` The cooled eiiluent is then passed from boiler 54 throughconduit 56 to a separator 51. In separator 51, ash and any unconvertedor partially-converted carbonbearing material' are removed from thegaseous effluent. Separator 51 may comprise a single or plura 'ty or"cyclone separators, a Cottrell precipitator, lters, or otherconventional means for separating iijnelyA divided solids from a gaseousmixture. A small amount of ash may be allowed to pass out of separator51 with the gases. Ash and carbon-bearing material separated in cycloneseparator 51 are removed therefrom through conduit 58 and passed to ahopper or storage vessel 59. From storage vessel 59 the ash andunconverted or partially converted coal are recycled or returned to lockhoppers l5 and i8 through conduits 5l and I9 by means of steamintroduced through conduit I9. In order to prevent the build-up of theash content in the system, a portion of the recycled ash and unconvertedor partially converted coal may be Withdrawn through conduit B2 fordisposal, or means may be provided for separating ne ash fromunconverted coal, such as by allowing ash Yto pass overhead in separator51. If desired, unconverted ash and coal may be recycled directly toconduit 35 and ultimately to combustion chamber 3s through conduits IS,62, and 63. The ash separated from the eilluent in cyclone separator 51may be disposed of directly, if desired, and this may often be thepreferred manner of operation where substantially all of 'thecarbonbearing material is converted to gaseous products. In such a casehopper 50 and its connecting conduits may be omitted.

A gaseous eiiluent substantially free from unconverted or partiallyconverted carbon-bearing material is passed from cyclone separator 51 ats. temperature of about 1000 F. or lower through ponduits 08 of aconventional Water heater 61. Water is passed to water heater 01lthrough conduit 6% and is heated'under pressure to a tem- .perature ofabout 400 F. If a pump is installed between heater 61 and subsequentboilers, then the pressure on the .water sideof `heater 61 need be onlythat necessary to suppressfvaporization therein. The heated water ispassed from water heater 61 through conduit 69 to a steam drum Ifadditional water is desired above that needed to cool the eilluent fromseparator 51, such Water may be introduced into conduit 59 throughconduit 1l. The heated water is then passed under pressure from steamdrum 12 through conduit A16 for indirect heat exchange with thecombustion chamber efuent in zol vfles 84 countercurrentl-y to adownward owing boiler 54. In boiler 54 water is vaporized under Y offheat exchange between ythe eiiluent er the eombustioncharnber ,1. 8 andwater, generally substantially all ofthe steam required in the processis produced with the resulting economical advatage of conservation ofheat. rlhis steam thus produced is passed through conduits 18 and 19 toconduitl 46 for preheating and introduction into combustion chamber 38,as previously described. Various methods of heat exchange, such as heatexchange of steam and/or oxygen in conduits 46 and i2 with the effluentsin conduits 3Q Vor 56, may become apparent to those skilled in the artwithout departing from the scope of this invention.

The gaseous mixture of hydrogen and carbon monoxide ata temperature ofabout 300 F. to 600 F. is passed through conduit 8l to scrubbing tower82. The entire system, including scrubber tower 82, is at approximatelythe pressure existing in conduit 36 after the expansionof' the coal vandgaseous mixture through nozzled. lIn scrubber 82 the gaseous effluentpasses upward through bafstream of water introduced'through conduits 83and 81. The liquid scrubbing medium removes fine ash entrained in theeffluent, which has not been removed by cyclone separator51, and alsoAfurther cools the gaseous effluent to a temperature of about F. orlower and condenses any Water vapor in the eiiluent. The scrubbingmediumco1- lects in the lower portion of scrubber 82 as indicated by theliduid phase 85. A major proportion of this liquid'pha'se is recycledthrough 'conduit'81 and cooler 88l to the upper portion of lowerportion-of scrubber 82 through conduit 89 v'for disposal oryremoval ofthe ash therefrom. 'The 'gaseous effluent -novv at a temperature'ofabout '100 F. or lower is removed from' 'scrubber' 82 through conduit 9i'and may be passed to storage (not shown)l vor maybev used directly as afuel, as 'a' feedrgas for the synthesis of hydrocarbons and oxygenatedorganic-compounds therefrom', or in the production o f"hydrogen. Thecoal lgasification veffluent contains, besides hydrogen andk carbonmonoxide, relatively'srnall amountslof carbon dioxide',v methane;ands'ulfur compounds, such a's lhydrogen sulfide. The sulfur compounds'lare pro'- v-duced'fro'm small amounts of sulfur in the coal.

These compounds present as impurities'may'(`v be removed from-theyeiilfuent by conventional means .(not shown).

l' A portion` of the' Agaseous` eiliuent comprising hy'- drogenandtcarbon monoxide may be returnedl tb "the lock'hopp'ers asa'pressuring gas or may be used as a conveying'or expansion medium aspreviously indicated. Recycling in the above manner is accomplished bypassing a portion of the gaseous effluent from conduit 9| throughconduit 9 2 vto knockout drum03` in vfhich entrained water is separatedfrom the gaseous effluent and removed from drum 93 throughconduit 94.The gaseous mixture substantially* free from entrained liquid is removedfrom drum 9'3 and passed through con#- duit 95,A to .compressort06.v Incompressor 96vthe gaseous eiluentis" compressed to the desired pressurefor repressu'ring the lock hoppers. The compressed efluent is thenpassedto asecond drum or accumulator 'S1 in which any condensate formed'aeeaoov present invention in" which steam is: passed through conduit|2|' and finely divided coke is picked up from conduit |34. Thepulverization and coking process in chamber'lZS from which the finelydivided coke is obtained will be discussed more fully hereinafter. Cokeand steam vare passed at a pressure, for example about 300 bustionelliuent is passed from combustion chamber |23 through conduit |21 tothe lower portion of a second enlarged chamber |23which is positionedvertically. Crushed coal is introduced into hopper |36 through conduit|31 and is pressured by a gas introduced therein through conduit |38.Hopper |36 may comprise a series of lock hoppers, in accordance with thedescription of Figure 1, in order to maintain the coal at the desiredhigh pressure. .Coal under a pressure of Vabout 500 to about 600 poundsper square inch gage is passed from hopper |33 through conduit |39 andis introduced into conduit |21 or directly into chamber |28 throughconduit |42, as shown. The coal and gas mixture from hopper |33 isexpanded through either nozzle |4| or nozzle |43, Vor both, with apressure drop of about 100 to about Y300 pounds per square inch underconditions such that coal' is pulverized to a size less than about 250microns, preferably less than about 10o microns. This iinely dividedcoal is suspended in an upward flowing gaseous mixture in chamber |28un'der conditions such that a pseudo-liquid dense phase of coalindicated by numeral |29 is 'formed therein. Both oxygen and steam maybe introduced into chamber |28 by means not shown,

if desired. The temperature of chamber |23 mat7 t.;

be substantially the same or lower than the temperature of combustionchamber |23 and at the temperature existing therein, for example about1000 F., the `finely divided coal is converted to Ycoke with theresulting volatilization .1

of the volatile components of the coal. The coke formed in chamber |28and present in the dense phase |29 is Withdrawn ytherefrom by means ofstandpipe |34. A small amount of the coke vmay be Withdrawn throughconduit |35 to prevent the building up of ash in the system.Alternatively or additionally to the Withdrawal of colte through conduit|35 a certain amount of ne ash may be permitted to pass out of chamber'|28 with the gaseous eflluent through conduit |23. The remainder of thecoke not Withdrawn through conduit |35 is introduced into conduit |2|,as previously described. A relatively dilute phase is present above thepseudo-liquid dense phase |29. The gaseous eflluent of the dilute phasepasses through a cyclone separator |3| in the upper portion of chamber|28 to remove entrained finely divided solids therefrom. These finelydivided entrained solids collected in cyclone separator |3| may bereturned to the pseudo-liquid dense phase |29 through conduit |32, asshown, ormay be removed from chamber |28 fordisposal, etc. A gaseouseffluent from combustion chamber |23 comprising hydrogen, carbonmonoxide and volatile components of the coal, such CII "14 as tars,naphthalene, anthracine, benzol, toluol, phenol, cresol, xylol, andnormally gaseous and liquid hydrocarbons as well as some nitrogen andsulfur compounds, is removed from the upper portion of chamber |28through conduit |33 and passed to a conventional product recovery'system (not shown) for the removal'of the valuable organic compoundsfrom the gaseous effluent.

A modification of the system of Figure 3 will be briefly described Withreference to Figure 4, in which modication the distillation of the vo'-latile components from the coal, as in chamber |28, is accomplished in ahigh velocity system similar to the system for the gasification of thecoke in chamber |23. Thus, the reaction eliluent from combustion chamber|23 is passed through conduit |21 to a vol'atilization chamber l5|comprising a cylindrical elongated conduit which may be positionedeither horizontally or vertically. VPulverized coal is introduced intoconduit |21 through conduit |39, as `previously described'. The lheat ofthe reaction effluent in conduit |21 volatilizes the volatile componentsof the coal in chamber |5| and the resulting mixture of hydrogen, carbonmonoxide, volatile components of the coal, and coke are passed fromchamber |5| through conduit |52 to separator '|53 comprising 'a settlingchamber or a cyclone separator. In

separator |53 the' coke is removed therefrom by gravity and passesthrough a standpipe |511 to conduit |2| for circulation to combustioncharnber |23 of Figure 3 inthe manner previously Adescribed. Thereaction effluent comprising carbon monoxide, hydrogen, and thepreviously mentioned volatile components and substantially free yfromcoke is removed from the top of separator |53 through conduit |56. Asmall proportion of the coke in standpipe |54 may be removed throughconduitY |51 in order to prevent the build-up of ash in the system. Theprimary difference in the modification of Figure 4 from that of Figure 3is thatthe distillation of the coal to produce coke and recovery of thevolatile components is accomplished in a high velocity system, usuallywith a velocity above about'a feet per second, without the formation ofthe conventional pseu- `do-liduid dense phaseof solids in thevolatilization zone but forming instead a relatively dispersed or dilutephase having a concentration of solids in the range described previouslywith regard to chamber 38 of Figure 1. In this manner `of operation ofthe coking chamber, opportunity for the sticking and agglomeraticn ofthe particles is minimized or substantially prevented.

The embodiment illustrated in Figures sand of the drawing isparticularlyl adapted to the recovery of volatile components of the coaland to the production of a high heating value gas. lt

may be desirable, therefore, to introduce a stripping gas into chamber|53 or conduits |34 or 54 by means not shown to aid in the removal ofvvolatile components from the coal or coke. Such a stripping gascomprises steam, recycle gas. etc.

In the embodiment shown in Figures 3 and 4 of the drawings, according toone modification, crushed coal may be introduced into conduit |21through conduit |39 or into chamber |23 through conduit |42 in a size'larger than that used in gasification of the coal in chamber |23. Forexample, crushed coal havingan vaverage diameter less than about 0.5inch is introduced through conduits |39 and |42 Without the use ofnozzles |4| and |43. In such a casethe pressure of the coal in hopper|3| i sY substantially the same as the pressure existing in conduit |21and chamber |28. The pseudo-liquid dense phase |29 of chamber |28 willcomprise particles of coal of a size greater than the size of the solidparticles in chamber |23. Coke is produced in chamber |28 of Figure 3 orchamber |5| of Figure 4 and is passed through conduit or standpipe |34or |54 to conduit |2|. In conduit |2| the mixture of coke and steam isexpanded in a nozzle (not shown) in conduit |2| to achieve the desiredneness for the gasication of the coal. The pressure in chamber 28 orchamber |5I and standpipe |34 is less than the pressure existing inconduit |2|, and, therefore, additional means must be supplied, such aslock hoppers, etc., to introduce the coke from conduit |34 or |54 intoconduit |2|.

In still another modification of the process of Figures 3 and 4, thereaction eiiiuent from combustion chamber |23 may be cooled such thatthe reaction is effected in chamber |28 or chamber |5| at a lowertemperature than in combustion chamber |23. A cooler or waste heatboiler (not shown) may be inserted in conduit |21 to cool the gaseouseflluent as much as 200 or 300 F., or even more, prior to introductionof the eiiiuent into chamber |28 or chamber |5I. In this manner theoperation of the volatilization stage at a lower temperature preventscracking of the volatile components and increases the recovery of highboiling products.

Figure 5 diagrammatically illustrates another embodiment of thisinvention for the gasification of coal. In this embodiment a mixture ofsteam and finely divided coal or coke of the type previously describedfor use in the gasication process is passed through conduit |1|, burner|12, to gasification or combustion chamber 814. Oxygen and steam areintroduced into burner |12 through conduit |13. rlhe gasiiication of thecoal is partially effected in chamber |14 under the previously describedconditions of operation using a relatively high velocity of gas suchthat a pseudo-liquid dense phase is not formed in chamber |14 and suchthat the residence time of the finely divided coal is preferablyapproximately the same as the residence time of the gaseous mixturepassing therethrough. According to this embodiment only partialgasification of the coal is effected in chamber |14 and the unconvertedcoal is removed therefrom with the gaseous eluent through conduit |16and passed to separator |11.

.Separator |11 may comprise a single or a series of conventionalseparators, such assettling chambers, Cottrell precipitators, cycloneseparators,

etc., for separating lunconverted coal from the gaseous effluent ofhydrogen and carbon monoxide. The gaseous efliuent of hydrogen andcarbon monoxide is withdrawn from separator 11 through conduit |18 forstorage or use as a fuel or for the synthesis of organic compoundstherefrom. Separated coal or carbon-containing material is removed fromseparatorv |11 through conduit |19 and passed to an enlarged chamber|8|. Enlarged chamber |8| is of ysuch size with respect to the gaseouseilluent passing upward therethrough that the coal is suspended in apseudo-liquid dense phase, as previously described. A pseudo-liquidphase of solids can be used satisfactorily at this lpoint in the systembecause the partial conversion in chamber v|14 hasreduced the tendencyof the solids to ag- 'glomerate Oxygen andl steam are introduced intochamber EBF through conduit |82 in the appropriate proportions forconverting the remaining unconverted or partially converted coal tohydrogen and carbon monoxide. The conditions of operation of chamber |8|are similar to the conditions of operation of chamber |14 and may bevaried within limits to achieve the desired result. The gas velocity, ofcourse, will be substantially lower than the gas velocity in chamber |14and usually lower than about 6 feet per second; for example, about 2feet per second. A portion of the pseudo-liquid dense phase may beremoved from chamber |8| through conduit or standpipe |83 in order toprevent the building up of ash in the system. The reaction eilluent ofhydrogen and carbon monoxide is removed from chamber |8| through conduit|84 and passed to conduit |16 where it is combined with the reactioneluent from conduit |14. Alternatively, or additionally, all or aportion of the reaction eilluent from chamber |8| may be passed througha conduit |86 to conduit |1| or directly into chamber 14.

The modification of Figure 5 permits treating the partially convertedcoal in chamber |8| with a large part of the fresh steam and oxygen,undiluted with product gases. Carbonaoeous residues which areunconverted in chamber |14 because of the short residence time areconverted in chamber 8| where a relatively longer residence time isobtained. Unconverted oxygen, and what would otherwise be an excessiveamount of unconverted steam, may pass overhead from chamber |8| tochamber |14 through conduit 8b. These unconverted agents are usefullyconsumed in chamber |14 because they are therein subjected to contactwith coal containing its reactive volatile components. In eiectV thisseparates the process into two stages with provision for countercurrenttreatment as between the two stages. Three or more such stages might beused in special instances. By operating in this manner, the temperaturein zone |14 may be appreciably reduced so that the production of methaneis favored and the temperature in chamber |8| may be several hundreddegrees higher than in chamber 14.

Although the figures of the drawings have been described with referenceto the explosion pulverization method for obtaining the desired nenessof coal for gasification, other methods for obtaining a nely dividedcoal, such as ball milling, and crushing, may be used without departingfrom lthe scope of this invention. In such instances where the coal ispulverized by ball milling or otherwise prior to introduction intothesystem, the various nozzles may be omitted and the expansion of thegaseous mixture containing the coal also eliminated. However, it may bedesirable to combine the two processes; that is, using a relativelyfinely divided coal below 250 microns in diameter and at the same timeexplosion pulverize this finely divided coal to obtain even more nelydivided coal. In place of the lock hoppers or standpipes shown in thedrawing, a Fuller- Kinyon pump or other screw conveyor device may beused without departing from the scope of this invention. Even certaintypes of reciprocating pumps may be used to introduce the coal into thesystem, such as those used on Stoker-nred furnaces. Another method ofbringing the coal feed to the operating pressure of the processcomprises mixing the coal with water to form a slurry and pumping theslurry to the desired pressure with a conventional slurry pump. The bulkof the slurry water is separated from the pressured coal 17- o bysettling, etc., and the thickened slurry is Dreheated to such an extentthat the water llashes to steam during the explosion pulverization.Liquid oils may be used in place of water.

In the embodiment of Figures 3 and 4, the coke produced in chmabers |29and I5i, respectively, may be recovered as a product of the process. Insuch instances coke is withdrawn through conduits |35 and 157,respectively.

It is usually necessary to aerate the standpipes in the process tomaintain the finely divided solids in the standpipes in a uidizedcondition in order that the solids will iiow. 'Ihe standpipes may beconveniently aerated by introducing into the lower portions thereof agas, such as steam or recycle gas. 'Y f Therfollowing example is offeredas a means of better understanding the application of the presentinvention to the gasification of coke to produce a gas rich in hydrogenand carbon monoxide. Although in the example specic conditions ofoperation are specied, these conditions should not be construed tounnecessarily` limit the present invention.

EXAMPLE Approximately 4,00 tons per day of Illinois coke breeze ischarged to a combustion zone similar in construction to the typepreviously described with reference to the present invention. Table Ibelow shows the proximate analysis and the ultimate analysis of thecoke.

Table I PROXIMATE ANALYSIS Wt. per geg;

Moisture Ash 24.35 Volatile matter wt. per cent 4.05 Fixed carbon do--..70.25

Total combustible 74.30

ULTIMATE ANALYSIS Wt. per gein;

Ash

Carbon 69.7

Hydrogen i 1.6

Nitrogen 1.3

Oxygen 2.1

Sulfur 0.6

Total 100.0

Table II Ste'zsxio g 500 p. s.l i. gage and 12,000Vp0unds/hr. Steam 300p. s. i. gage and 22,500 pounds/hr.

95% purity oxygen 800 F y5,000,000 s. o. Fg/day. Steam (total) -n 1.03pound/pound coke. Oxygen (pure) 6.9 S.' C. F./pound coke. The cokebreeze is pulverized by means oi explosion pulverization to obtain thenecessary particle iineness. The coke feed, initially crushed to 8 or 10mesh, along with the 500 pound steam which is in the amount of vabout0.3 pound per pound of solid is expanded from about 500 pounds persquare inch to about 295 pounds per square inch gage through a suitablenozzle and the resulting powdered coke and steam is passed into thecombustion chamber. The size distribution of the coke is within theapproximate range of 65 to 95 per cent through a 200 mesh screen. The300 pound steam and oxygenare admixed with 'the expanded steam Aandcoke. The initia1 cony centration of coke inthe combustion chamber on Ythe basis of total feed steam and oxygen is about 0.04 per cubic foot ofgas at standard conditions. On the basis of steam and oxygen, at theoperate ing pressure and temperature of 1800 F., the concentration isapproximately 0.2 pound per cubic foot of gas.'y As the conversionproceeds in the reaction chamber as the gases flow through that chamberthe gas volume increases but the solids weight decreases so that thesolids concentrations become even lower. The outlet concentration atflowing condition is about 0.045 pound per cubic foot of gas. Since therelatively low solids concentration is maintained in the reaction zoneby virtue of the relatively high velocity of the gaseous stream passingtherethrough, the linear velocity based upon outlet conditions is about42.5 feet per second.

It is not necessary to employ such severe pulverization conditions thatall of the particles of coke are small enough to be converted in thesingle pass through the combustion chamber. The coarser particles in thecombustion chamber effluent which may contain an average of about 30weight per cent of unconverted carbon may be recycled to the inletstream and subjected to further conversion,'to be more fully discussedhereinafter. The combustion chamber comprises an foot length of standardInsidline pipe of 20 inch inside diameter positioned horizontally onsuitable concrete supports. The combustion chamber, further, has a thinunstressed liner of Atype 309 alloy (25 per cent chromium; 12 per centnickel steel) surrounded by a layer of Baldwin- I-Iill type #5 blockinsulation approximately 3 inches thick.

The combustion chamber effluent comprising hydrogen and carbon rmonoxidedischarges into a' vertical fire tube waste heat boiler of conventionaldesign. This Aboiler absorbes 20,000,000 B. t. u.s per hour from theproduct gas and in so doing cools the gas from about 1800 F. to aboutl260 F. In this marmer approximately 24,000 pounds per hour of steam isgenerated at 550 pounds per square inch gage pressure (12,000 pounds perhour more than required by the process). The rst waste heat boiler isfollowed 'by a second waste heat boiler of similar construction whichcools the effluent from the first boiler to a temperature of about 710F. The second boiler absorbs about 18,500,000 B. t. u.s per hour fromthe effluent andY generates about 22,500 pounds per hour of steam at 350pounds per square inch gage pressure. This quantity of steam produced inthe second `waste heat boiler is approximately the -amount of 350 poundssteam required for the process. Any deficiency in 350 poundfsteam as aresult of the changes in nature of the feed stock can be made up bydiverting some of the excess steam from the first boiler.

Thercooled eiiluent from the second Waste heat boiler is introduced intoa, cyclone separator. In this separator the larger solid particlescontaining vunconverted. carbon are, removed fromA the eiliuent. About45 per cent of the solids entering the cyclone separator 'are removed.These solids are collected and recycled with the feed stream. Theheavier solid particles contain on an average about 30 weight per centof unconverted carbon. The ash in the recycled solids amounts to about60 per cent of the net quantity of ash in the feed. Unseparated solidsin the efliuent from the separator contain only about 5 weight per centof carbon. l All of the ash entering the process is ultimatelyeliminated with the separator efliuent.

. 19 The gas analysis of the gaseous eiiluent on a dry 'b asis at thispoint in the pro-cess is shown in Table Ill beiow constitutes aboutk30,000,000 standard cubic feet per day of gas..

Table III Vol. percent Nitrogen 1.4 Hydrogen 41.6 Carbon monoxide 41.5Carbon dioxide 14.8 Methane 0.5 Hydrogen suliide 0.2

Total 100.0

The eiiluent gas leaving the cyclone separator at a temperature ofapproximately 710 F. is heat exchanged in a tubular heat exchanger withthe feed water for the two waste heat boilers. The water enters thisheat exchanger from a deaerator at a, temperature of about 225 F. andleaves the heat exchanger at a temperature of about 400 F., afterabsorbing approximately 8.500.000 B. t. u.s per hour or" heat and aftercooling the eiiluent gas to about 440 F.

From this last heat exchanger the cooled effluent is passed to aconventional battled scrubbing tower in which the effluent gas is cooledto a final temperature of approximately 100 F. to condense unconvertedsteam and to remove nely divided entrained ash. The scrubbing tower ismaintained at a pressure of approximately 275 pounds per square inchgage. The scrubbing is accomplished by circulating a stream of the waterslurry through an outside cooler and over baflies within the tower. Asmall amount of fresh water is pumped over two conventional bubble-captrays in the top section of the tower to Wash back slurry entrained fromthe baffled section.

Carbon dioxide and hydrogen suliide may be removed by water scrubbing ina subsequent tower. The analysis of the gaseous effluent from the carbondioxide removal tower is shown in Table IV. The quantity of the gasleaving the scrubbing tower is approximately 26,000,000 standard 'cubicfeet of puried gas per day with a hydrogen to carbon monoxide mol ratioof about 1:1. The gaseous eiiiuent is suitable for the direct synthesisor hydrocarbons and oxygenated Certain valves, coolers., heaters, pumps,accumula-tors, storage vessels, etc., have been omitted from thedrawings as a matter of convenience and their use and location willbecome obvious to those skilled in the art. The size and length ofcertain conduits of the drawings may not be proportional to the amountof uid passing therethrough and the distances travelled are merelydiagrammatical. It is not intended to limit any particular location ofinlets and outlets of the apparatus shown in the draw-ings. The exampleand theory in connection with the invention are offered as illustrationsand should not be construed to unnecessarily limit the invention.

Having described my invention, claim:

1. A process for the gasification of carbon-containing material toproduce a gas rich in hydroeen and carbon monoxide and substantiallyfree from methane which comprises suspending in a reaction zone a casingtype coal in finely divided form containing initially no more than aminor proportion by weight of material whose average particle diameteris greater than about 2.50 microns in a fiowing gaseous mixturecomprising oxygen and steam under conditions such that hydrogen andcarbon monoxide are produced as products ofA the process, supplying therequired heat of conversion to said reaction zone by direct heatexchange, maintaining the linear gas velocity suiiiciently high suchthat the heaviest particles of finely divided solid continuously moveinthe direction of flow oi the gases, maintaining the temperature ofreaction above 1800" F. and belowl 2600o F. and a lpressure betweenabout 250 and about 1000 pounds per square inch gage and a residencetime of solid material in said reaction zone less than about 5 seconds,and removing a gaseous eiiuent containing hydrogen and carbon monoxidefrom said reaction zone substantially tree from methane as a product ofthe process.

2. The process of claim l in which both steam and oxygen are introducedtangentially into one end of the reaction zone.

3. A process for the gasication of a caking type coal to produce a gasrich in hydrogen and carbon monoxide which comprises passing a gaseousmixture of oxygen, steam and 'finely divided caking type coal which coalhas a particle size less than about 250 microns upward through areaction zone at 'a linear gas velocity between about 8 and about 100feet per second such that theheaviest particles of finely divided coalcon- Vtinuously move in the direction of flow of the gases and slippageofthe iinely'divided coal is substantially negligible, maintaining afeed ratio to said reaction zone Aoi oxygen between about ltand about 15cubic feet per pound of coal .and of steam between about `0.2 and aboutipounds per pound of coal, maintaining said reaction Vzone at atemperature between about 1800 F'. and about 2600 F. and under apressure between about 250 and about 1000 pounds persquare inch gage,maintaining the temperature of the inside of the reaction zone at ahigher temperature than the temperature on the outside of the reactionzone, maintaining the concentration of coal in said gaseous mixtureflowing through said reaction zone between about 0.01 and about 0.5pound of coal per cubic foot of gas-.at standard conditions oftemperature and pressure, maintaining a residen-ce time of powderedsuspended coal in said reaction zone less than about 5 seconds, wherebya gaseous eiuentV is produced rich in carbon monoxide and hydrogen andsubstantially free from methane, and withdrawing from .reaction zone ata linear gas velocity between about 8 and about 100 feet per second suchthat l the heaviest particles of finely divided coal continuously movein the direction of ow of the gases, maintaining said reaction zone at atem- 2l perature between about 1800 F.an'd'about 2600" F. land under apressure between about 250 and about 1000 pounds per square inch gage,maintaining the temperature of the inside ofthe reaction zone Yat ahigher temperature than the temperature on the 'outside of the reactionzone, maintaining aresidence time of powdered suspended coal in'saidreaction zone not substantially greater than about 10 seconds, whereby agaseous effluent is produced rich in carbon monoxide .and hydrogen andsubstantially free from methane, and withdrawing from said reaction zonesuch an eliluentV as a product of the process. 5. A process for thegasication of a oaking type coal which comprises suspending in areaction -zone a powdered caking type coal in a owing gaseous mixturecomprising oxygen and steam under conditions such that hydrogen isproduced as a product of the process, supplying the required heat ofconversion to said. reaction zone by direct heat exchange, maintaining alinear gas velocity sufliciently high such that the heaviest particlesof powdered coal continuously move in the directionrof now of the gases,maintaining the temperature of reaction above 1800o F. and below 2,600oF'. and a pressure between about 250 and about 1000 pounds per squareinch gage and a residence time of powdered coal in said reaction zoneless than about 5 seconds, removing a gaseous effluent containinghydrogen and substantially free from methane and containing powderedunconverted coal from said reaction zone, separating powderedunconverted coal from said gaseous eluent and recycling the separatedunconverted coal to said reaction zone.

6. A process for the gasification of a caking type coal which comprisesexpanding a mixture of steam and caking type coal under conditions suchthat coal is reduced to a size less than about 250 microns, passing theresulting mixture of steam and nely divided coal to a reaction zone,introducing oxygen and steam into said reaction zone adjacent the pointof introduction of said mixture of steam and finely divided coal,maintaining a linear gas velocity within said reaction zone suiiicientlyhigh such that the heaviest particles of finely divided coalcontinuously move in the direction of flow of the gases, convertingcoal, steam and oxygen to hydrogen and carbon monoxide in said reactionzone, maintaining the temperature of reaction above about 1800L7 F. andbelow about 2500 F. and the pressure between about 250 and about 1000pounds converted coal from said reaction zone, separating unconvertedcoal from said eiiuent, and recycling the-separated unconverted coal tothe original gaseousmixture ofsteam and coal.

7. A process for the gasication of a caking type coal to produce a gasrich in hydrogen and carbon monoxide which comprises passing a gaseousmixture of oxygen, steam and powdered caking type coal throughrareaction Zone at a sufficiently high linear gas velocity such thatV theheaviest particles of coal are continuously moved in the direction offlow of the gases under conditions such that coal and steam are con- 22verted to hydrogen and carbon monoxide, main'- taining the temperatureof the inside of the reacltion zone at a higher temperature than thetemperature on the outside of the reaction zone, maintaining atemperature of conversion between about 1800 F. and about 2600 F. and alpressure between about 250 and about 1000 pounds per square inch gage,maintaining the concentration of coal in said gaseous mixture flowingthrough Asaidreaction Zone less than about 1 pound of coal per cubicfoot of gas, maintaining a residence time of coal in said reaction vzonenot substantially greater than about 10 seconds, whereby a gaseouseiiiuent is produced rich in hydrogen and carbon monoxide andsubstantially free from methane, and withdrawing such a gaseous effluentfrom said reaction zone as a product of the process.

i8. A process for the gasication of a caking type coal to produce a gasrich in hydrogen and carbon monoxide which comprises passing a gaseousmixture of oxygen, steam and powdered caking type coal through areaction zone at a suiiiciently high linear gas velocity such that theheaviest particles of coal are continuously moved in the direction oflow of the gases under conditions such that substantially all of thecoal is converted in a single pass through said reaction Zone, supplyingsubstantially all of the required heat oi conversion to said reactionzone by direct heat exchange, maintaining a temperature of conversionabove about 1800o F. and below about 2600" F. and a pressure betweenabout 250 and about 1000 pounds per square inch gage, and maintaining aresidence time of coal in said reaction zone .not Substantially greaterthan about l0 seconds, whereby a gaseous effluent rich in hydrogen andcarbon monoxide and substantially free from methane is produced, andremoving such an ellluent from said reaction zone as a product of theprocess.

9. A process for the gasification of a caking type coal which comprisespassing a stream of steam to a mixing zone in which oxygen is introducedinto said mixing zone angularly and circumferentially at a plurality ofpoints to the stream of steam, introducing powdered 'caking type coalinto said stream of steam passing to said mixing zone whereby powderedcoal is carried therewith to the mixing zone and is admixed with theoxygen therein, passing the gaseous stream containing powdered coal andsteam through an elongated reaction zone from said mixing zone,supplying sufficient oxygen to said mixing zone to burn nely dividedcoal in an amount to supply the required heat for the con version ofcoal and steam to hydrogen and carbon monoxide, passing the gaseousstream of powdered coal and steam through said reaction zone at asuicientlyhigh linear velocity such that the heaviest particles ofpowdered coal are continuously moved in the direction of now of thegases therein, maintaining a temperature of reaction above about1800 F.and below about' 2600u F. in said elongated reaction zone and a pressureVbetween about 250 and about 1000 pounds per square inch gage,maintaining a residence time of powdered suspended coal in Asaidreaction zone not substantially greater than about 10 seconds, whereby agaseous eiiiuent rich in hydrogen and carbon monoxide and substantiallyfree from ethane is produced, removing from said reaction zone such aneffluent containing ash formed in said reaction zone, separating ashfrom said gaseous elluent. and re- Lcovering the gaseous eiiiuent as a'produotjoi A,the

process. l

10. The process of claim 9 in which oxygengis introduced into saidmixing zone tangentially to said stream of steam `and powdered coal suchthat a whirling motion is imparted vto the mixture leaving the mixingzonev andv passing into said. reaction zone.

11. A process for the gasification oi a caking type coal which comprisespassing a .gaseous mixture of steam and powdered caking type coalthrough an elongated reaction zone suieient to permit a residence timenot substantially greater than about 1() seconds for substantialconversion of coal and steam to hydrogen and carbon monoxide,maintaining a linear gas yVelocity in said reaction zone such thatpowdered coal continuously moves in the direction of flow of the gasesin a highly dispersed condition whereby the tendency of the caking typecoal to stick together is minimized at the temperature of con Version,maintaining a temperature of oonversion between about 1200o F. and.about 2600o F. and a pressure between about 250 and about 1000 poundsper square inch gage, maintaining the temperature of the inside o thereaction zone at a higher temperature than the temperature on theoutside of the reaction zone, sup-plying sufficient oxygen to saidreaction zone to raise the temperature of the reaction zone to thedesired level for the conversion reaction, whereby a gaseous efiluentcomprising hydrogen and carbon monoxide and substantially free1frommethane is produced, removing from .said reaction Zone such an.effluent and containing .nely divided entrained ash, separating ashfrom said eluent, and recovering the eiiuent as a product of theprozess.

NORMAN L. DICKINSON.

References Cited in the file 0f this patent STATES Number Name Date1,899,887 Thiele Feb. 28, '1933 '1,983,943 Odell Dec. 11, 1934 2,111,579Winkler et al. Mar. 22, 1938 2,385,508 Hammond 1 Sept. 25, 19452,414,586 vEglofl Jan. 21, 19.47

' 2,482,187 ,Johnson ...7 Sept. 20, 1949 FOREIGN PATENTS Number CountryvDate 9,498 Australia Jan. 25, 1928 of 1927 y 286,404 Great Britain Mar.8, 1928 528,338 Great Britain Oct. 28, v1940 532,342 Great Britain Jan.22, 1941 585,354 Great Britain Feb. 5, 1947 OTHER REFERENCES Chemicaland Metallurgical Engineering, vol. 24 (1921), pages 600 to 604.

Chemical Engineering, Jan. 1947, pages to 108.

Chemical Engineering Process, vol. 43 (Aug. 1947), pages 429 to 436.

4. A PROCESS FOR THE GASIFICATION OF A CAKING TYPE COAL TO PRODUCE A GASRICH IN HYDROGEN AND CARBON MONOXIDE, WHICH COMPRISES PASSING A GASEOUSMIXTURE OF OXYGEN, STEAM AND FINELY DIVIDED CAKING TYPE COAL WHICH COALHAS A PARTICLE SIZE LESS THAN ABOUT 250 MICRONS UPWARD THROUGH AREACTION ZONE AT A LINEAR GAS VELOCITY BETWEEN ABOUT 8 AND ABOUT 100FEET PER SECOND SUCH THAT THE HEAVIEST PARTICLES OF FINELY DIVIDED COALCONTINUOUSLY MOVE IN THE DIRECTION OF FLOW OF THE GASES, MAINTAININGSAID REACTION ZONE AT A TEMPERATURE BETWEEN ABOUT 1800* F. AND ABOUT2600* F. AND UNDER A PRESSURE BETWEEN ABOUT 250 AND ABOUT 1000 POUNDSPER SQUARE INCH GAGE, MAINTAINING THE TEMPERATURE OF THE INSIDE OF THEREACTION ZONE AT A HIGHER TEMPERTURE THAN THE TEMPERTURE ON THE OUTSIDEOF THE REACTION ZONE, MAINTAINING A RESIDENCE TIME OF POWDERED SUBPENDEDCOAL IN SAID REACTION ZONE NOT SUBSTANTIALLY GREATER THAN ABOUT 10SECONDS, WHEREBY A GASEOUS EFFLUENT IS PRODUCED RICH IN CARBON MONOXIDEAND HYDROGEN AND SUBSTANTIALLY FREE FROM METHANE, AND WITHDRAWING FROMSAID REACTION ZONE SUCH AN EFFLUENT AS A PRODUCT OF THE PROCESS.